This is the interim report of Deliverable 6.5 “Design and Evaluation of School-based Citizen Science Activities”, the final version of which is formally due on M36. D6.5 reports on work conducted within Work Package 6 (WP6) and more specifically under Sub-Task 6.4.2 (Set-up and evaluation of innovative school-based citizen-science activities). The NKUA team who is responsible for authoring and submitting D6.5 is also the leading partner in Sub-Task 6.4.2. D6.5 reports on the work being carried out under Sub-Task 6.4.2. This work involves a set of interrelated and mutually contributing actions that have been conceived to form the strategy (general design model) for facilitating, supporting, implementing and evaluating school-based citizen science activities and projects that make use of the Cos4Cloud CO platforms. These actions, which are aligned to the Cos4Cloud project"s goals to support the widening of current citizen science practice through the engagement of new target audiences, school population.